How to Change the Coolant in a 2006 Yamaha TTR125: Step-by-Step Guide

Shop parts for a 2006 Yamaha TTR125 Dirt Bike.

Maintaining your 2006 Yamaha TTR125 is crucial for performance and longevity. Although the TTR125 uses an air-cooled engine rather than a liquid-cooled one, riders sometimes refer to changing engine fluids or mistakenly look for coolant information because of terminology crossover from other Yamaha trail bikes. For the TTR125, there is no liquid coolant in the radiator system—instead, focus on keeping your engine oil fresh and checking for adequate airflow around the cooling fins.

If you meant another Yamaha model (such as the WR125 or YZ125, which are liquid-cooled), the steps would generally include:

  • Removing the radiator cap to allow air in during draining
  • Locating the coolant drain bolt under the engine or radiator
  • Draining old coolant into a container
  • Flushing with distilled water if desired
  • Reinstalling the drain bolt with a new washer
  • Refilling with the correct 50/50 premixed coolant or factory-recommended formula
  • Running the engine briefly with the cap off to burp air bubbles out of the system
  • Rechecking and topping off coolant to the proper level once the system cools

With the TTR125 being air-cooled:

  • No radiator or coolant fluid to change—maintenance focuses on oil changes and maintaining the cooling fins free from mud or obstructions for proper heat dissipation.
  • Inspect for damage to the cylinder fins and maintain airflow, especially after muddy or dusty rides.
  • Use high-quality engine oil and change it at regular intervals to ensure optimal engine temperature control.

Notes for TTR125 Owners:

  • If you observe overheating issues, check for blocked airflow, old oil, or excessively rich/lean carb mixture rather than coolant issues.
  • Review your owner's manual for the proper oil type and maintenance schedule specific to your TTR125 year and revision.
  • Never add coolant or attempt to locate a radiator drain on the TTR125, as it is not equipped with a liquid-cooling system.

Keeping your TTR125 in top shape is all about clean airflow and fresh oil. For all maintenance supplies and upgrades, MotoSport has you covered.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.